The present invention relates to electromagnetic vibrators which are particularly useful for driving linear-type pumps. The invention also relates to a leaf spring construction particularly useful in such electromagnetic vibrators.
Linear-type pumps, which include electromagnetic vibrators for reciprocating a plunger, generally provide a number of important advantages over rotary-type pumps, including the following: long life, low noise level, high efficiency, compact structure, smooth air flow, and simple maintenance eliminating the need for lubrication. In one type of linear pump, the pumping member driven by the electromagnetic vibrator is a diaphragm; and in a second type of linear pump, the pumping member is a piston. Generally speaking, electromagnetic vibrators suitable for driving diaphragms are not suitable for driving pistons unless they include low friction guiding bearings which constrain the movements of the plunger to longitudinal displacement. Such guiding bearings, however, increase wear and tear, and decrease efficiency.
One type of electromagnetic vibrator uses a plunger containing soft ferromagnetic material, and another type uses a plunger containing permanent magnets. Electromagnetic vibrators utilizing soft ferromagnetic material are generally less costly than those utilizing permanent magnets.